As in known in art, brushless DC (BLDC) motors can include an external electronic switch synchronized to the rotor position that replaces a mechanical commutator. In conventional BLDCs, Hall effect sensors may be mounted on the windings for rotor position sensing and closed-loop control of the electronic commutator.
Field Oriented Control (FOC) is a conventional technique for sensor-less and windowless control in BLDC systems. Known FOC processing may require the real-time amplitude of the phase current in at least two phases and complex computations, such as so-called d-q transforming computations. Typical FOC implementations require a current sensing circuit, such as a phase shunt resistor, bus shunt resistor, or dedicated current sensor, an ADC, and a processor to perform FOC plus so-called position observer processing.